Switching in the PT-symmetric nonlinear periodic structures

We study the dynamic behavior and switching of optical pulses in the PT-symmetric structure with the additional periodic modulation of the Kerr nonlinearity. In such structure the change of a refractive index by an intense optical radiation causes the change of the PT-symmetry breaking threshold while the gain/loss value is constant. As the result the system can move from the full PT-symmetry state to the broken PT-symmetry or vice versa. It is shown that despite the self-pulsation instability these transitions can be observed in the switching of long enough optical pulses. Furthermore, such active structures allow to control the amplitude enhancement of the transmitted pulses.